Complete RuboCop style guide links

[oiahoon]

Summary

• update outdated or mismatched RuboCop rule references in the style guide
• add the remaining local StyleGuide links to the corresponding current cop configuration

Why

Several guide rules either lacked local metadata in config/default.yml or still referenced cops that have since been renamed. Completing the mapping makes RuboCop's cop details point users back to the matching project guidance without changing any cop behavior.

Fixes #133.

Validation

• focused guide/config mapping check: 60 mappings, 55 unique cops, 0 missing
• bundle exec rake test (123 runs, 177 assertions)
• bundle exec rubocop (31 files, no offenses)
• bundle exec rake
• git diff --check

[issyl0]

Thank you! 🤩